An engine bench system measures various characteristics of an engine by joining an engine which is a test piece and a dynamometer by a connection shaft, and controlling the throttle aperture of the engine with a throttle actuator, while using the dynamometer as a power absorber of the engine. A shaft torque meter that detects the shaft torque, which is the torsional torque, is provided to the connection shaft, and upon using the dynamometer as the power absorber, shaft torque control which matches this shaft torque to a predetermined shaft torque command is performed.
Patent Document 1 shows a shaft torque control device according to an I-PD control method. With the engine bench system, resonance may occur in the connection shaft due to the pulsating torque generated at the engine. Therefore, the shaft torque control device of Patent Document 1 realizes the characteristics of the engine bench system by a two-inertia system transfer function, and sets a gain parameter used in I-PD control by designating the frequency of the pole of the fourth-order closed-loop transfer function obtained by the joining of this transfer function and the I-PD control device, as a mechanical resonance frequency of the engine bench system. With the shaft torque control device of Patent Document 1, shaft torque control having a resonance suppressing result thereby becomes possible.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2009-133714